The Louisiana Purchase opened up the West, allowing people to journey all the way to California and Oregon. Between the late 1830's and 1860's more than 250,000 Americans traveled west. The idea of traveling west was the Manifest Destiny, which was the idea that the nation was meant to spread to the Pacific. What attracted settlers to the west side was that there was more opportunity to farm fertile soil and enter the fur trade. A few east-to-west routes have been carved, by the 1840's. These include, the Oregon Trail, the California Trail, and the Santa Fe Trail. All this over-land traffic effected the Plain Indians because they relied on the buffalo herds and they feared they would die off or migrate somewhere else. To keep peace with the Indians, the federal government negotiated the Treaty of Fort Laramie in 1851.
